The present invention relates to a method and apparatus for testing to determine the presence of occult blood in fecal matter, and more particularly to a method and apparatus for testing to determine the presence of occult blood in the private environment of a person's home without the necessity of handling the fecal matter prior to or during the test procedure and for eliminating handling of the test materials once the test is completed.
Over 100,000 persons in the United States are affected by cancer of the colon and rectum per year, occurring equally in both the male and female. When the number of colorectal cancers occurring each year is combined with the number of cancers occurring in other digestive organs, including the esophagus and stomach, such cancers of the digestive system account for more occurrences of cancer than any other single form of the disease. Contrary to many other forms of cancer, early diagnosis and treatment of digestive tract cancer does result in a cure rate of 80% to 90% of those persons affected by the disease. If, however, the disease is not detected until the later stages, the cure rate drops drastically to 25% or less. Thus early detection of the disease is critical to successful treatment of digestive tract cancer.
Most, but not all cancers of the digestive tract bleed to a certain extent. This blood is deposited on and in fecal matter excreted from the digestive system. The presence of blood in fecal matter is not normally detected, however, until gross bleeding, that is, blood visible to the naked eye, occurs. Most advance cancers cause gross bleeding.
It is known that digestive tract cancers in the early stages also tend to bleed, giving rise to occult (hidden) blood in the fecal matter. Test equipment and test procedures have been developed for use by physicians in testing for the presence of occult blood in fecal matter. One of the most successful tests is manufactured and sold by Smith Kline Diagnostics, a division of Smith Kline Instruments, Inc. of Sunnyvale, California under the trademark Hemoccult and disclosed in U.S. Pat. No. 3,996,006 issued to J. F. Pagano. Briefly, the Pagano test employs an absorbent paper impregnated with a guaiac reagent and encased in a special test slide having openable flaps on both sides of the test slide. To use the Pagano test slide, the physician or a lab technician must obtain a sample of fecal matter, smear it onto the guasiac impregnated paper by opening the panel on one side of the test slide, and thereafter close the panel. A panel on the opposite side of the test slide is then opened and a nonaqueous developing agent is applied to the guaiac impregnated paper. If occult blood is present in the fecal matter smeared on the opposite side of the paper, the guaiac reaction will dye the paper blue, providing a positive indication of the presence of blood in the fecal matter.
Although the Pagano test is excellent for use by physicians in their offices and by diagnostic laboratories, it is not the type of test which is readily adaptable for use by the ordinary person because of his adverse reaction to handling fecal matter. As stated above, the Pagano test requires that a specimen of fecal matter be obtained. Normally a specimen is obtained by procuring a sample on the end of a spatula or a wooden depressor, which is then used to smear the specimen on the paper in the Pagano test slide. Once the sample is obtained and the test procedure completed, both the test slide and the spatula or depressor must be disposed of. Disposal of the used materials can and does present a physical problem to, if not an adverse psychological reaction from, the ordinary person. Thus, the ordinary person is not likely to use the Pagano test because of its uncleanly nature (at least apparently so to the ordinary person) and because of the disposal problems associated with the used test slide and spatula or depressor. Additionally, the ordinary person does not necessarily have the skill required to analyze, and thus form accurate conclusions from, the test results.
It has also been suggested that the ordinary person could initiate the Pagano test in his home and then forward the test slide to his physician or a laboratory for addition of the developing agent and analysis of the test. This procedure however, is not viable as it requires cold storage of the test slide and specimen if there is a significant time lapse before the test can be completed. Certainly, the ordinary person does not wish to store a fecal specimen in his household refrigerator, normally the only cold storage available to him, until he can present the specimen to his physician or an appropriate laboratory.
Another test for occult blood is suggested by D. E. Fonner in U.S. Pat. No. 2,838,377. The Fonner test as disclosed can be effected in a toilet bowl containing fecal matter. The basic test reagents employed by Fonner are o-tolidine, o-toluidine, and benzidine. These reagents in the presence of blood and other reactants produce a dye visible to the naked eye. Although the Fonner test appears to be a solution to the problem of finding a viable home test for occult blood, it has not met with success for two reasons. First, the above-listed reagents are in themselves known to cause cancer and thus are not suitable for general public distribution. Additionally, the Fonner reagents have a relatively high rate of providing false indications of the presence of occult blood.
Thus, to date, the use of the Pagano test, the Fonner test and other similar tests has been limited primarily to physicians and diagnostic laboratories or has proven unworkable or unreliable. Although this limitation might not at first glance present a significant problem, it does limit the early detection of digestive tract cancers, primarily because patients will not see a physician until other symptoms of digestive tract cancers, such as gross bleeding, manifest themselves. Thus, early detection of cancer of the digestive tract still does not occur with the majority of patients who contract the disease.
It is therefore a broad object of the present invention to increase the early detection rate of cancers of the digestive tract. It is a further object of the present invention to provide a test method and apparatus that can be employed by the ordinary person, preferably in his own home on a periodic basis, to determine the presence of occult blood in the person's fecal matter. It is a further object of the present invention to provide such test methods and apparatus that do not require the patient to handle his fecal matter during the test procedure and to provide test procedures and apparatus that do not have to be handled during performance of the test and do not have to be handled for disposal. It is another object of the invention to provide such test methods and apparatus that are easily conducted and understood by the ordinary person and that will provide an easily recognizable, analyzable, reproducible, and reliable test result.